Detergent compositions comprising a source of alkalinity, a surfactant or surfactant package combined with other general washing chemicals have been known for many years. Such materials have been used in laundry products, warewashing compositions, CIP cleaners, hard surface cleaners etc. Virtually any cleaner containing a source of alkalinity that is designed or formulated for dilution into an aqueous based composition can be used within this broad general concept. The powder dishwasher detergents are disclosed in, for example, in Dos et al., U.S. Pat. No. 3,956,199, Dos et al., U.S. Pat. No. 3,963,635. Further, Macmullen et al., U.S. Pat. No. 3,032,578 teach alkaline dishwashing detergents containing a chlorine source, an organic phosphonate, a surfactant composition and a water treating agent. Similarly, Almsted et al., U.S. Pat. No. 3,351,557, Davis et al, U.S. Pat. No. 3,341,459, Zimmerman et al., U.S. Pat. Nos. 3,202,714 and 3,281,368 teach built liquid laundry detergent comprising a source of alkalinity and nonionic surfactant materials.
Powdered general purpose, warewashing and laundry detergents have been used for many years. The manufacture and use of solid block cleaning compositions were pioneered in technology disclosed in Fernholz et al., U.S. Reissue Pat. Nos. 32,763 and 32,818 and in Heile et al., U.S. Pat. Nos. 4,595,520 and 4,680,134. Gansser, U.S. Pat. No. 4,753,441, presents a solid detergent technology in a cast solid form using a nitrilotriacetate sequestrant. The solid block detergents move quickly replaced a large proportion of conventional powder and liquid forms of warewashing detergents and other products in commercial, institutional and industrial laundry, warewashing etc. washing and cleaning markets for safety convenience and other reasons. The development of these solid block cleaning compositions revolutionized the manner in which many cleaning and sanitizing compositions including warewashing detergent compositions are manufactured and used in commercial, institutional and industrial cleaning locations. Solid block compositions offer certain advantages over conventional liquids, powders, granules, pastes, pellets and other forms of detergents. Such advantages include safety, improved economy, improved handling, etc.
In the manufacture of powdered detergents, powdered ingredients are typically dry blended or agglomerated in known manufacturing facilities to produce a physically and segregation stable powder composition that can be packaged, distributed and sold without substantial changes in product uniformity. Liquid materials are commonly blended in aqueous or nonaqueous solvent materials, diluted with a proportion of water to produce an aqueous based liquid concentrate which is then packaged, distributed and sold. Solid block detergent compositions are commonly manufactured and formed into a solid often using a hardening mechanism.
In the manufacture of solid detergents, various hardening mechanisms have been used in the manufacture of cleaning and sanitizing compositions for the manufacture of the solid block. Active ingredients have been combined with a hardening agent under conditions that convert the hardening agent from a liquid to a solid rendering the solid material into a mechanically stable block format. One type of such hardening systems is a molten process disclosed in the Fernholz patents. In the Fernholz patents, a sodium hydroxide hydrate, having a melting point of about 55°-60° C., acts as a hardening agent. In the manufacturing process, a molten sodium hydroxide hydrate liquid melt is formed into which is introduced solid particulate materials. A suspension or solution of the solid particulate materials in the molten caustic is formed and is introduced into plastic bottles called capsules, also called container shaped molds for solidification. The material cools, solidifies and is ready for use. The suspended or solubilized materials are evenly dispersed throughout the solid and are dispensed with the caustic cleaner.
Similarly, in Heile et al., an anhydrous carbonate or an anhydrous sulfate salt is hydrated in the process forming a hydrate, having a melting point about 55° C., that comprises proportions of monohydrate, heptahydrate and decahydrate solid. The carbonate hydrate is used similarly to the caustic hydrate of Fernholz et al to make a solid block multicomponent detergent. Other examples of such molten processes include Morganson, U.S. Pat. No. 4,861,518 which discloses a solid cleaning concentrate formed by heating an ionic and nonionic surfactant system with the hardening agent such as polyethylene glycol, at temperatures that range greater than about 38° C. to form a melt. Such a melt is combined with other ingredients to form a homogeneous dispersion which is then poured into a mold to harden. Morganson et al, U.S. Pat. No. 5,080,819 teaches a highly alkaline cast solid composition adapted for use at low temperature warewashing temperatures using effective cleaning amounts of a nonionic surfactant to enhance soil removal. Gladfelter, U.S. Pat. No. 5,316,688 teaches a solid block alkaline detergent composition wrapped in a water soluble or water dispersible film packaging.
Solid pelletized materials are shown in Gladfelter, U.S. Pat. Nos. 5,078,301, 5,198,198 and 5,234,615 and in Gansser U.S. Pat. Nos. 4,823,441 and 4,931,202. Such pelletized materials are typically made by extruding a molten liquid or by compressing a powder into a tablet or pellet. Extruded nonmolten alkaline detergent materials are disclosed in Gladfelter et al., U.S. Pat. No. 5,316,688.
These powdered, pellet, liquid and solid block detergent compositions have acceptable cleaning properties for most commercial purposes. Materials introduced into customer based testing or sold in the market place have achieved commercially acceptable and uniformly passing cleaning results. However, we have found, under certain conditions of fabric, ware, substrate, water hardness, machine type, soil type and load, etc., some stains have resisted removal during the cleaning process. We have found a number of waxy-fatty soils that appear to harden on the surface of ware and resist even highly alkaline cleaning detergents under certain conditions. Such soils are common in the cleaning environment and are typically hydrophobic materials that can form thin films on the surface of a variety of items. We have found that lipsticks soils can act as a soil model for this broad hydrophobic waxy-fatty soil genus. Lipsticks typically contain a large proportion of lipid, fatty and wax-like materials in a relatively complex mixture including waxy compositions, fatty materials, inorganic components, pigments, etc. The wax-like materials typically include waxes such as candelilla wax, paraffin wax, carnuba wax, etc. Fatty ingredients typically include lanolin derivatives, isopropyl isostearate, octyl hydroxy stearate, castor oil, cetyl alcohol, cetyl lactate, and other materials. Such lipid materials are typically difficult to remove under the best of circumstances. More importantly, we believe the castor oil component of lipstick formulations are unsaturated materials that can act like drying oils and can oxidatively crosslink in thin films to form crosslinked or pseudocrosslinked soil layers that are highly resistant to detergents. The formation of lipstick soils and other similar thin film, fatty or waxy, soils resistant to removal has been a stubborn soil requiring attention for many years. Under certain circumstances such waxy-fatty soils can remain on glassware, cups, flatware, dishware, etc.
A substantial need exists to improve the cleaning properties of solid block detergent materials and particularly as it relates to hydrophobic (fatty, crosslinked fatty or waxy) soils for which lipstick stains are a good model.
A number of avenues can and have been explored in such an improvement attempt. Examples of research areas can include experimentation in the effects of water temperature, sequestrants that reduce water hardness, the effect of various alkaline sources, the effects of sequestrant types and blends, solvents effects and surfactant choice. The surfactants that can be used in the cast solid materials are vast. There are large numbers of anionic, nonionic, cationic, amphoteric or zwitterionic, etc. surfactants that can be used singly or in combinations of similar or diverse types. Even after substantial experimentation, waxy-fatty soils continue to pose a serious problem.